From the time man first engaged in organized combat, one of the issues he has faced has been the identification of friendly forces. Prior to the widespread use of drab coloured uniforms for low visibility, brightly coloured uniforms were used to identify one group of soldiers from another. However, this practice has, for obvious reasons, fallen into disuse. The problem of identifying friendly from unfriendly forces, however, remains.
One area in which this problem is critical, if not potentially fatal, is in the delivery of ordnance. The rise of so-called “smart weapons” has increased the accuracy of ordnance delivery, but, sadly, has also increased the casualty rates of so-called “friendly fire” incidents. In the first Persian Gulf conflict of the early 1990s, US Defence Department analysis identified a staggering 49% of all US casualties as stemming from friendly fire. Because of such reports, the US Defence Department conducted extensive research into the area of friendly/enemy discrimination in the battlefield.
One program introduced to reduce such friendly fire casualty rates was the Battlefield Combat Identification System or BCIS. BCIS was used by both ground and air forces. Based on radar technology, a small transmitter and receiver was provided to every combat vehicle in the US Army. The device received and sent signals that identified itself to friendly forces. While this system would be effective for vehicles, it is not suitable for individual soldiers and is costly. It could cost as much as $40,000 per vehicle for the system.
Other systems, also based on wireless technology, such as that disclosed in, U.S. Pat. No. 4,851,849 and U.S. Pat. No. 4,694,297, offer a different solution. However, all of these alternatives are quite costly on a per unit basis and do not offer a solution which can be easily deployable or be deployable to the single soldier level. None of these systems can also be deployable on ordnance. Such ordnance, once launched, cannot be aborted. Thus, a targeting error can lead to tragic results.
A solution is needed that is cost-effective, easily deployable and, ideally, deployable on individual soldiers. Such a solution should also be capable of being deployed on ordnance to avoid human error and misidentification by combatants such as pilots. This would avoid such tragic incidents as the bombing of Canadian soldiers by the US Air Force in Afghanistan in 2002 and the bombing of allied Kurdish fighters and US Special Forces troops, again, by the US Air Force in 2003.
One possible problem with optics-based solutions in their use in broad daylight. The brightness of sunlight can overpower most optics based solutions such as that disclosed in U.S. Pat. No. 5,966,227. Specifically, detecting a return optical signal can be difficult as the return optical signal can get overwhelmed by sunlight. It is therefore an object of the present invention to mitigate if not overcome the shortcomings of the prior art.